Active Sites Flashcards
How is an enzyme substrate complex formed?
It is when an enzyme acts on its substrate where it makes temporary bonds to the active site.
What are the two models/ theories called?
The lock and key model and the induced fit model.
What does the lock and key model suggest?
It suggests that the substrate of the enzyme is imagined fitting into the active site, the active site is complementary to the substrate. No other molecules will fit so no other reaction will occur.
What does it mean by the term ‘enzyme specificity’?
It means that the enzyme is specific to its substrate.
What does the induced fit model suggest?
Observation showed that an enzymes shape was slightly altered when binding to the substrate which suggests that it is flexible and not rigid. This model shows an enzyme shape alters slightly in order to accommodate the substrate.
What is an example of an enzyme which proves the induced fit model?
The enzyme lysozyme is an anti bacterial enzyme found in human saliva, mucus and here’s the active site is a groove in the sugars on the bacterial cell wall fit into it. The group closes over the sugars and the molecule changes shape around the sugars and hydrolyses the bonds holding them together.
What is the induced model fit of enzyme action?
The substrate collides with the active site where the active site moulds around the substrate molecule and is held in position by oppositely charged groups on the amino acid active site. An enzyme substrate complex is now formed. A change in its 3-D shape can cause strain on the substrate as it brings the two reactants together allowing the reaction to occur more easily. This weakens the chemical bonds and allowing them to break more easily lowering the activation energy. An enzyme product complex is now formed, with the product no longer fitting in the active site so it is released.
